1. Field of the Invention
This invention relates to a novel reactive polymer, a method for the manufacture thereof and use thereof. More particularly, this invention relates to a reactive polymer obtained by causing an unsaturated aziridine compound possessing one aziridinyl group and at least radically polymerizable unsaturated group to react with polymer containing a free carboxylic group, to a method for the manufacture of the reactive polymer and use of the reactive polymer.
2. Description of the Prior Art
The term "reactive polymer" as used in this specification means a polymer which possesses a reactive group "capable of inducing the so-called radical reaction or participating in this reaction" owing to the action of heat, ultraviolet light, electrom beam, a free radical generator or the like.
A few reactive polymers of this nature have been suggested to date. One of them makes use of the so-called esterification reaction. For example, the reactive polymers obtained by the method which makes use of the reaction of polymers containing a free carboxylic group with an unsaturated hydroxyl compound or unsaturated glycidyl compound or the reaction of polymers containing a hydroxyl group or glycidyl group with an unsaturated carboxylic acid compound have been known to the art. The esterification reaction, however, is liable to entail side reactions such as the polymerization of an unsaturated group because the reactants are generally held under harsh temperature conditions for a fairly long time. As means for diminishing this hazard, moderation of reaction conditions as by addition of a large amount of a polymerization inhibitor to or introduction of oxygen into the reaction system or use of an esterification catalyst in the reaction system has found recognition. The reactive polymers obtained from such a reaction system often contain excess polymerization inhibitor or residual catalyst. These extraneous substances possibly cause coloration and retardation of reaction. Thus, the reactive polymers are of poor quality.
Besides, use of the carbamate reaction has been proposed. For example, the reactive polymers obtained by combining polymers possessing a hydroxyl group with an unsaturated hydroxyl compounds through the medium of a diisocyanate compound have been known to the art. Again in the case, use of a catalyst typically of an organic tin compound is nesessary for the promotion of the reaction and, moreover, selective reaction between the hydroxyl group of the polymer and the hydroxyl group of the unsaturated compound and between one of the isocyanate groups of the diisocyanate compound and the other isocyanate group is difficult to accomplish. To enhance the selectivity of the reaction, the plurality of steps of the reaction must be carried out sequentially instead of being performed all at once. This method, therefore, has the disadvantage that the operation of manufacture entails this complexity of the reaction.
As another piece of the prior art, Japanese Patent Publication SHO 57 (1982)-56,507 discloses a method for producing a reactive copolymer by copolymerizing an unsaturated aziridine compound with other copolymerizable monomer to from a copolymer having an aziridinyl group in a side chain thereof and subsequently causing an unsaturated carboxylic acid compound to react upon the aziridinyl group of the copolymer. The production of the reactive polymer by this method, however, has a serious disadvanctage from the practical point of view. Specifically, during the copolymerization of the unsaturated aziridine compound and during the addition reaction of the unsaturated carboxylic acid compound, the reaction system is exposed to harsh conditions such that the ring opening reaction of the aziridinyl group tends to induce an increase of viscosity or, in an extreme case, the phenomenon of gelation. Further, it has been ascertained that the reaction system involved in this method abhors inclusion thereof of water or a compound containing an amino group, a hydroxyl group or a carboxylic group other than the carboxylic group originating in an unsaturated carboxylic acid compound because the presence therof promotes the ring opening of the aziridinyl group. Adoption of this method, therefore, necessitates payment of ample attention to the purification of raw materials and the selection of manufacturing devices. What is more important is the fact that the unsaturated aziridine compound is incapable of copolymerizing with such a monomer as (meth)acrylic acid or hydroxyethyl (meth)acrylate which contains active hydrogen. For those skilled in the art, this method has not proved sufficiently feasible.
An object of this invention, therefore, is to provide a novel reactive copolymer, a method for the manufacture thereof and use thereof.
Another object of this invention is to provide a novel reactive polymer possessing a reactive group "capable of inducing a radical reaction or participating in this radical reaction," a method for the manufacture thereof and use thereof.